This application relates to an electrical control circuit for a brushless synchronous machine, wherein an inverter circuit is used to start the engine as well as to allow excess voltage from a capacitor to flow back toward the brushless synchronous machine if there is an undue rise in the voltage across the capacitor.
Generators are known and are utilized to generate electricity for an associated system. The use of a generator in starting and generating modes in aircraft application has been realized in a variable-speed, constant frequency (VSCF) power generating systems. In such a system the variable-frequency power is rectified and provided a DC link (bus) to a controllable static inverter. The DC bus provides power to other loads connected to the bus. A bus capacitor is mounted in parallel with these loads.
Under certain conditions, if the load on the bus is reduced, the voltage across the bus capacitor will rise. In the past, the bus capacitor has needed to be sufficiently large to handle this voltage rise.
In addition, other elements such as a transient suppressor, which may be a shunt regulator, have been connected across the bus via a power switch to provide a temporary load to compensate for the lower load condition from the bus during such instances.
The result is that a large capacitor and large transient suppressor have been required.
In the system shown in U.S. Pat. No. 6,838,860. The control is not utilized to respond to an undue transient voltage across a bus capacitor.